Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPdata collection is to provide insights into the spatial distribution of surface contamination, and toguide subsequent soil sampling. [required]A.9.3Surface Soil SamplingSurface soil sampling will be used to address areas inaccessible to GWS data collection, toresolve hot spots identified by the GWS data, and to evaluate the presence, absence, and/or extentof surface contamination above surface soil CG w requirements based on GWS results.• Hot Spots. If GWS data indicate the presence of contamination that possibly exceeds“hot spot” (CG emc ) standards or an isolated elevated area is identified that appearsindicative of a discrete release, the location of concern will be sampled with a biasedsample. Within WMA 1, hot spots will be biased sampled if they are outside the plannedWMA 1 deep excavation footprint. If biased samples are collected from a particularlocation, they will be collected from two depth intervals: 0 – 15 cm, and 15 cm – 1 m.The 0–15 cm samples will be analyzed for the 12 radionuclides of potential interest inaddition to the 18 ROI. One down-hole gamma scan will be conducted from each biasedlocation. The purpose of these samples is to resolve GWS anomalies, evaluate theappropriateness of the current ROI list, and verify the absence of additional ROI.[contingent]• CG w Sampling. Surface soil sampling may be conducted after the GWS to further clarifyresults, with the level and nature of sampling dependent on GWS results. For WMA 1,surface soil CG w sampling in response to GWS results will primarily focus on areas thatare currently not paved and that are not within the planned WMA 1 excavation footprint.oIf GWS results indicate contamination impacts above background levels but thatsurface soil contaminant levels exceeding surface soil CG w requirements are unlikely,the area of interest will be systematically sampled using a triangular grid with adensity of one sample per 400 m 2 . One sample will be collected from each locationrepresentative of a 0-15 cm depth interval. The purpose is to document the maximumactivity concentrations present in surface soils within WMA 1. [contingent]Rev. 1 A-14